This invention relates to threadless feed mechanisms and, more particularly, to an apparatus for converting between rotary and axial motion.
In my prior patent entitled "Feed Mechanism", U.S. Pat. No. 3,081,639 of Mar. 19, 1963, which is hereby incorporated by reference, I disclose a feed mechanism having inner and outer radially spaced apart races, a cage positioned between the races and elongated rollers carried by the cage. The rollers have axes inclined with respect to the axes of the races and the rollers are constantly in contact with the facing surfaces of the inner and outer races.
With respect to the apparatus described in my prior patent, the feed mechanism converts rotary motion of the outer race to axial movement of the inner race. In the apparatus of my prior patent, movement of the two races relative to each other is limited by the length of the outer race because the cage cannot move axially beyond the ends of the outer race. In other words, the maximum axial movement of the inner race is limited by the axial length of the outer sleeve which limits the axial distance which the cage can travel.
The present invention provides a different approach to the movement of the cage relative to the races thereby avoiding the aforementioned limitation.